This invention relates to crystalline salt and solvate forms of the antibiotic syn-7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-(3-methyl-3H-imi dazolo-[4,5-c]-pyridinium-5-ylmethyl)-3-cephem-4-carboxylate (the Antibiotic). The Antibiotic is described in European patent application No. 138552, published 24 April 1985, and is a broad spectrum semi-synthetic antibiotic. Salts of the Antibiotic with strong acids also are disclosed.
The Antibiotic is difficult to obtain in the highly pure form required for pharmaceutical administration and also exhibits solubility and stability characteristics which are undesirable in a drug. Therefore, a form of the Antibiotic more amenable to pharmaceutical uses is needed. In addition, it is advantageous to have intermediates which facilitate the purification of the Antibiotic.